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Medium to Long Term Regulation of Blood Pressure
Who are the authors mentioned in the document?
Susan Posky, Asma Alanazi, PhD, and Mohammed Alassiri, PhD.
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Medium to Long Term Regulation of Blood Pressure
What is the main topic of the document?
Medium to Long Term Regulation of Blood Pressure.
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Medium to Long Term Regulation of Blood Pressure
What is medium to long term regulation of arterial blood pressure?
It refers to the mechanisms that maintain blood pressure over extended periods, primarily through blood volume regulation and hormonal influences.
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Medium to Long Term Regulation of Blood Pressure
What role does blood volume regulation play in blood pressure?
It helps maintain arterial blood pressure through mechanisms like capillary fluid shifts.
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Hormonal Control of Blood Pressure
What is the significance of hormones in blood pressure regulation?
Different hormones play crucial roles in the medium and long term regulation of blood pressure.
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Mechanisms of Blood Pressure Regulation
What are the two basic mechanisms for regulating blood pressure?
Short-term mechanisms and long-term mechanisms.
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Renin-Angiotensin-Aldosterone System (RAAS)
When is renin released by the kidneys?
When the arterial pressure falls too low.
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Medium to Long Term Regulation of Blood Pressure
How does the renal-body fluid system affect arterial pressure?
It acts slowly but powerfully.
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Hormonal Control of Blood Pressure
From which gland is ADH secreted?
The posterior pituitary gland.
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Renin-Angiotensin-Aldosterone System (RAAS)
What does RAAS stand for?
Renin-Angiotensin-Aldosterone System.
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Overall Control of Arterial Blood Pressure
What do mechanisms that return blood volume to normal after overload act as?
Pressure controllers and blood volume controllers.
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Mean Arterial Pressure (MAP)
What is Mean Arterial Blood Pressure?
It is the average blood pressure in a person's arteries during one cardiac cycle.
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Overall Control of Arterial Blood Pressure
What are the two main problems the pressure control system faces during severe bleeding?
1. Rapidly returning arterial pressure to a high enough level. 2. Returning blood volume and arterial pressure to normal levels.
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Overall Control of Arterial Blood Pressure
What is the primary goal of the pressure control system during severe bleeding?
To ensure survival by rapidly restoring arterial pressure.
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Mean Arterial Pressure (MAP)
How is Mean Arterial Pressure (MAP) calculated?
MAP = Diastolic BP + 1/3 pulse pressure.
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Short Term Regulation Mechanisms
What do short-term mechanisms regulate?
Blood vessel diameter, heart rate, and contractility.
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Overall Control of Arterial Blood Pressure
How do neural, hormonal, and autoregulatory mechanisms interact in blood pressure control?
They work together to maintain overall control of arterial blood pressure.
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Mean Arterial Pressure (MAP)
What does cardiac output (CO) refer to?
The volume of blood the heart pumps per minute.
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Renin-Angiotensin-Aldosterone System (RAAS)
What triggers the release of renin in the RAAS?
Low blood pressure or low sodium levels.
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Hormonal Control of Blood Pressure
What does Angiotensin II stimulate to help regulate blood pressure?
Secretion of aldosterone, secretion of ADH, and activation of the thirst center.
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Renin-Angiotensin-Aldosterone System (RAAS)
How does the RAAS affect blood pressure?
By increasing blood volume and constricting blood vessels.
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Medium to Long Term Regulation of Blood Pressure
What is closely intertwined with long-term control of arterial pressure?
The homeostasis of body fluid volume.
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Mean Arterial Pressure (MAP)
What generates pressure in the circulatory system?
The heart pumping blood into the systemic circulation.
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Determinants of Blood Pressure
What components make up Total Peripheral Resistance?
The resistance offered by all the arterioles in the circulatory system.
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Mean Arterial Pressure (MAP)
What happens if the Mean Arterial Pressure (MAP) falls below 60 mm Hg for an extended time?
Blood pressure will not be high enough to ensure circulation, resulting in ischemia.
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Short Term Regulation Mechanisms
What role does the sympathetic nervous system play in short-term arterial blood pressure regulation?
It affects total peripheral resistance and cardiac pumping ability.
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Determinants of Blood Pressure
How does excess blood volume affect the heart?
It drives the heart to greater cardiac output.
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Mechanisms of Blood Pressure Regulation
How many mechanisms are involved in blood pressure regulation?
Approximately 7 mechanisms.
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Hormonal Control of Blood Pressure
What is the primary function of antidiuretic hormone (ADH)?
To regulate the volume and osmolality of urine.
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Mean Arterial Pressure (MAP)
What is central venous pressure (CVP)?
The pressure in the thoracic vena cava, reflecting the amount of blood returning to the heart.
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Hormonal Control of Blood Pressure
What does ANP stand for?
Atrial Natriuretic Peptide.
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Mean Arterial Pressure (MAP)
What factors can cause variations in MAP?
Age, sex, weight, posture, mood, physical condition, stress.
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Mechanisms of Blood Pressure Regulation
How does ANP affect vascular smooth muscle?
It relaxes vascular smooth muscle.
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Medium Term Regulation Mechanisms
What does capillary fluid shift refer to?
Redistribution of fluid within the vascular-interstitial compartments due to changes in MAP.
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Hormonal Control of Blood Pressure
How does Angiotensin II affect blood pressure?
It is a hormone that plays a significant role in regulating blood pressure.
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Determinants of Blood Pressure
What is the formula for Blood Pressure?
Blood Pressure = Cardiac Output X Total Peripheral Resistance.
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Determinants of Blood Pressure
What role do arterioles play in blood pressure?
The diameter of arterioles affects Total Peripheral Resistance.
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Short Term Regulation Mechanisms
What is the time frame for short-term regulation of blood pressure?
Reacts rapidly, within seconds or minutes.
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Determinants of Blood Pressure
Why does MAP not decrease significantly in the aorta and large arteries?
Because the aorta and arteries have little resistance to flow.
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Determinants of Blood Pressure
Where does 50-70% of the pressure drop occur within the vasculature?
Within the resistance vessels.
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Hormonal Control of Blood Pressure
What is the role of Angiotensin II in blood pressure regulation?
It acts to restore blood pressure and blood volume.
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Renin-Angiotensin-Aldosterone System (RAAS)
What does aldosterone do in the body?
It promotes sodium and water retention, increasing blood volume.
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Hormonal Control of Blood Pressure
How do catecholamines affect the kidneys?
They stimulate NaCl reabsorption by the proximal tubule, thick ascending limb of the loop, distal tubule, and collecting duct.
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Hormonal Control of Blood Pressure
What triggers the release of Atrial Natriuretic Peptide (ANP)?
It is released mainly from the right atrium in response to stretch and high blood volume.
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Determinants of Blood Pressure
What is the relationship between blood volume and arterial pressure?
Excess volume leads to greater arterial pressure.
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Mechanisms of Blood Pressure Regulation
What are the three groups of mechanisms for blood pressure regulation?
1. Rapid response (seconds or minutes), 2. Intermediate response (hours), 3. Long-term regulation (days, months, years).
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Overall Control of Arterial Blood Pressure
What regulates arterial pressure?
Several interrelated systems, each performing specific functions.
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Medium to Long Term Regulation of Blood Pressure
What is pressure natriuresis?
The doubling of salt output in response to an increase in arterial pressure.
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Medium to Long Term Regulation of Blood Pressure
What is the effect of a few mm Hg increase in arterial pressure on renal output?
It can double both renal output of water and salt.
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Normal Arterial Blood Pressure Values
What does systolic blood pressure represent?
Maximum arterial pressure after ventricular contraction.
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Mean Arterial Pressure (MAP)
What are the effects of ANP on blood volume and resistance?
Decreased blood volume, decreased resistance, and decreased MAP.
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Medium Term Regulation Mechanisms
What happens to fluid when there is a fall in capillary pressure?
Fluid is absorbed by osmosis from the interstitial compartment into the circulation, increasing blood volume and pressure.
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Mean Arterial Pressure (MAP)
What are the three determinants of Mean Arterial Pressure (MAP)?
Cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP).
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Short Term Regulation Mechanisms
What is the baroreceptor reflex?
A response to changes in blood pressure.
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Medium to Long Term Regulation of Blood Pressure
What happens to renal output of water with a slight increase in arterial pressure?
It can double due to pressure diuresis.
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Hormonal Control of Blood Pressure
What effect does ADH have on the kidneys?
It increases the retention of water.
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Renin-Angiotensin-Aldosterone System (RAAS)
What is the primary function of the Renin-Angiotensin-Aldosterone System?
To regulate blood pressure and fluid balance.
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Determinants of Blood Pressure
What are considered resistance vessels in the circulatory system?
Small arteries (100 μm) and arterioles (20 μm).
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Hormonal Control of Blood Pressure
What hormones are classified as catecholamines?
Adrenaline and noradrenaline.
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Hormonal Control of Blood Pressure
How does angiotensin II affect blood vessels?
It causes vasoconstriction.
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Determinants of Blood Pressure
What factors determine Cardiac Output?
Heart Rate and Stroke Volume.
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Medium Term Regulation Mechanisms
What occurs when blood pressure is high?
Fluid shifts from blood to tissues, causing the tissues to swell.
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Renin-Angiotensin-Aldosterone System (RAAS)
What is the role of renin in blood pressure regulation?
It raises arterial pressure in several ways, helping to correct the initial fall in pressure.
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Short Term Regulation Mechanisms
What does the chemoreceptor reflex respond to?
Oxygen, carbon dioxide, and pH levels of blood.
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Short Term Regulation Mechanisms
What is the central nervous system ischemic response?
Control of arterial pressure by the brain's vasomotor center in response to diminished brain blood flow.
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Overall Control of Arterial Blood Pressure
What must happen for the circulatory system to establish full normality after severe bleeding?
Blood volume and arterial pressure must return to their normal levels.
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Mean Arterial Pressure (MAP)
What does a low MAP indicate?
Inadequate blood flow to organs and shock.
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Determinants of Blood Pressure
What characteristics do resistance vessels have?
They are less elastic and have a thicker layer of smooth muscle.
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Hormonal Control of Blood Pressure
What effect do catecholamines have on blood vessels?
They cause vasoconstriction (α1 receptors) and vasodilation (β2 receptors).
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Hormonal Control of Blood Pressure
What is the role of vasopressin (ADH) in blood pressure regulation?
It causes vasoconstriction and water retention, taking about 30 minutes to work.
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Hormonal Control of Blood Pressure
What is the role of Atrial natriuretic peptide (ANP) in blood pressure regulation?
It is involved in hormonal mechanisms that help regulate blood pressure.
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Medium to Long Term Regulation of Blood Pressure
Why is fluid intake and output balance important for long-term survival?
To maintain homeostasis of body fluid volume.
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Medium Term Regulation Mechanisms
What is capillary fluid shift?
Redistribution of fluid within the vascular and interstitial compartments due to changes in Mean Arterial Pressure (MAP).
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Renin-Angiotensin-Aldosterone System (RAAS)
What is renin?
A proteolytic enzyme synthesized in the kidneys.
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Mean Arterial Pressure (MAP)
What is systemic vascular resistance (SVR)?
The resistance to blood flow offered by the systemic blood vessels.
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Short Term Regulation Mechanisms
Which nerve innervates the stretch receptors in the carotid sinuses?
Herring’s nerve, a branch of the glossopharyngeal nerve.
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Renin-Angiotensin-Aldosterone System (RAAS)
What is the role of angiotensin II in the RAAS?
It constricts blood vessels and stimulates aldosterone release.
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Normal Arterial Blood Pressure Values
What does diastolic blood pressure represent?
Minimum arterial pressure during ventricular relaxation.
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Normal Arterial Blood Pressure Values
How is pulse pressure calculated?
Pulse pressure = Systolic - Diastolic pressure.
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Hormonal Control of Blood Pressure
What is the function of Vasopressin in blood pressure regulation?
It is a hormone that helps regulate blood pressure.
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Medium Term Regulation Mechanisms
What types of control are included in medium term mechanisms?
Hormonal control (Endocrine) and other mechanisms.
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Medium to Long Term Regulation of Blood Pressure
What primarily determines long-term regulation of blood pressure?
Regulation of blood volume through the Renin-Angiotensin-Aldosterone System (RAAS).
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Renin-Angiotensin-Aldosterone System (RAAS)
What activates the Renin-Angiotensin-Aldosterone System (RAAS)?
Low blood volume, low blood pressure, low renal blood flow, and the Sympathetic Nervous System (SNS).
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Hormonal Control of Blood Pressure
What is the effect of aldosterone on renal function?
It decreases renal excretion of sodium.
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Hormonal Control of Blood Pressure
What are the effects of Atrial Natriuretic Peptide (ANP) on blood pressure?
It causes vasodilation and decreases blood volume by increasing urinary Na+ and water loss, thereby decreasing blood pressure.
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Normal Arterial Blood Pressure Values
What is the normal arterial blood pressure for a young adult man?
Around 120/80 mmHg (Systolic/Diastolic).
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Hormonal Control of Blood Pressure
What peptide is produced by cardiac ventricles?
Brain Natriuretic Peptide (BNP).
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Mean Arterial Pressure (MAP)
What does MAP reflect in the body?
The haemodynamic perfusion pressure of vital organs.
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Hormonal Control of Blood Pressure
What is the effect of ADH on renal function?
It decreases renal excretion of water.
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Hormonal Control of Blood Pressure
What role do catecholamines play in blood pressure regulation?
They are involved in hormonal mechanisms that regulate blood pressure.
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Mechanisms of Blood Pressure Regulation
What is the primary mechanism of action of ANP?
Increased loss of Na+ and water in urine and vasodilation.
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Medium Term Regulation Mechanisms
What is stress relaxation of vasculature?
The response of blood vessel smooth muscle to changes in blood volume and flow.
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Hormonal Control of Blood Pressure
Which hormones are involved in the medium term regulation of blood pressure?
Catecholamines, Angiotensin II, Vasopressin, Atrial natriuretic peptide (ANP).
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Overall Control of Arterial Blood Pressure
What are the three types of regulatory mechanisms that maintain blood pressure?
Short term, medium term, and long term mechanisms.
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Medium to Long Term Regulation of Blood Pressure
How do long term regulation mechanisms adjust blood pressure?
By adjusting the blood volume (Endocrine and Renal).
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Hormonal Control of Blood Pressure
What does ANP promote in the kidneys?
NaCl and water excretion.
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Short Term Regulation Mechanisms
How quickly do short term mechanisms respond to changes in blood pressure?
Within seconds or minutes.
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Short Term Regulation Mechanisms
What type of reflexes are involved in short term blood pressure regulation?
Reflexes mediated by the nervous system (Neural).
